“We heard a big boom,” witness Kennon Murphy told CBS 2′s Hazel Sanchez. “We went over here and looked and that’s when we saw the crane was down.”

It happened just before 7:30 p.m. at a construction site above the No. 7 line subway extension project. A Fire Department spokeswoman said an 80-foot section and a 40-foot section from an upright crane became dislodged.

Investigators said the crane cable snapped, sending the boom plummeting. That massive arm of steel crushed one of the workers, while another worker suffered severe trauma to his leg after being hit by debris.

Firefighters said rescuing the workers from the 60-foot pit where they were working was not easy. The precarious effort was undertaken using ropes before the workers were rushed to Bellevue Hospital.

“It was extremely dangerous because we had construction material that wasn’t stable and the crane was leaning against the building. It was an expedited removal, but we had some difficulty because of the trauma,” said EMS Deputy Chief Jack Sullivan.

Frank Basile’s brother-in-law had been working at the site. He said he ran to the location after hearing about the collapse and was relieved to hear his family was safe.

“I feel a little choked up because I’m thinking who it might be…like I said I’ve seen someone die before falling, so it’s a little emotional,” he said.

Police crime scene investigators were gathering evidence Tuesday night even though they said there is no reason to expect any criminality or negligence at this point.